Lid construction for breathing apparatus

ABSTRACT

A breathing assistance apparatus has a lid and latch assembly configured for one-handed operation. The apparatus also includes a hinge assembly that separates when over-rotated but that reengages upon closing of the lid onto the main body of the apparatus.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 CFR 1.57. Thepresent application is a continuation of U.S. application Ser. No.15/405,847, filed Jan. 13, 2017, which is a continuation of U.S.application Ser. No. 14/667,499, now U.S. Pat. No. 9,546,025, filed Mar.24, 2015, which is a continuation of PCT International Application No.PCT/NZ2013/000175, filed Sep. 23, 2013, which claims priority to U.S.Provisional Application No. 61/705,340, filed Sep. 25, 2012, theentirety of each of which is hereby incorporated by reference herein.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention generally relates to respiratory devices. Moreparticularly, the present invention relates to respiratory devices inwhich respiratory gases are supplied at a positive pressure afterpassing over a surface of liquid in a reservoir.

Description of the Related Art

CPAP treatment of obstructive sleep apnea involves the delivery ofpressurized, breathable gas, usually air, to a user's airways using aconduit and a user interface, such as a mask. The gas pressures employedfor CPAP typically range from about 4 cm H2O to about 28 cm H2O at flowrates of up to about 180 L/min (measured at the user interface), dependupon the requirements of the user. The pressurized gas acts as apneumatic splint for the airway of the user. As such, the pressurizedgas reduces the likelihood of collapsing of the airway.

SUMMARY OF THE INVENTION

CPAP machines include an airflow generator to supply the pressurized gasand many CPAP machines include a heated water bath or other source ofwater for humidification of the pressurized gas. CPAP machines often areused in bedrooms or other sleeping quarters and are placed onnightstands, for example. As such, reducing the footprint of CPAPmachines is desirable. In addition, given the limited space ofnightstand tops, CPAP machines often are pushed as close to a wall aspossible.

Because of the cramped spaces in which CPAP machines are used, easymanipulation of a lid or other component used to enclose a waterreservoir or the like is desired. Preferably, the lid or other suchcomponent can be easily pivoted about hinges. More preferably, thehinges are configured to be generally flush with, or recessed into, theadjoining outer surfaces Even more preferably, the hinges provide arestraint against forces generated by air pressure within the machine(e.g., vertical forces with a generally horizontal lid) while allowingdetachment of the lid when the lid is overextended during opening.

Moreover, to improve the ability to access the water reservoir, the lidpreferably carries a latch mechanism such that a user can open the lidwith a single hand. In other words, the latch can be operated and thelid can be opened with a single hand and, preferably, with the singlehand in a single position. Such configurations are a welcomedimprovement over configurations requiring one hand to operate the latchand another hand to subsequently raise the lid.

In some configurations, a breathing assistance apparatus comprises a lidand a main body with the lid and the main body selectively enclosing acavity. The lid comprises a button member and at least one hingeassembly.

In some configurations, the lid further comprises a component adapted tobe engaged with one or more fingertips while the button member isdepressed.

In some configurations, the button member is spring biased away from theat least one hinge assembly.

In some configurations, the at least one hinge assembly allows pivotalmovement of the lid relative to the main body.

In some configurations, the hinge assembly comprises at least one postand at least one support, the supports overlying the post and the postbeing positioned inboard of an outer perimeter of the lid.

Preferably, the hinge assembly comprises a clip extending along at leastan axial length of the post, the clip being positioned on an oppositeside of the post from the supports such that the post is capturedbetween the clip and the supports.

In some configurations, the at least one hinge assembly comprises aguide structure and cam structure, the guide structure and the camstructure configured to cause sliding movement of the post duringrotation of the post.

In some configurations, the guide structure comprises a guide surface,wherein in use the guide surface contacts the cam structure to move thelid from a detached state to an attached state relative to the main bodyvia the sliding movement of the post as a result of closing motion ofthe lid.

Preferably, the sliding movement only occurs when the lid is moved froma disengage state to an engaged state with respect to the main body.

Preferably, the sliding movement of the post is substantially horizontalwith the supports being positioned at least vertically above the postwith the lid in the closed position.

In some configurations, the at least one support defines an opening thatpermits the at least one post to pass through the opening such that inuse the lid can be moved from a detached state to an attached staterelative to the main body.

In some configurations, a method of opening a lid of a breathingapparatus comprises moving a button member toward an engagementcomponent to unlatch the lid and then rotating the lid to an openedposition without the user having to reposition a hand.

In some configurations, a method of engaging a lid on a main body of abreathing apparatus comprises placing a post alongside at least onesupport member with the lid in an open position, pivoting the lid towarda closed position such that at least one engaging structures formed onthe lid and at least one engaging structure formed on the main bodycause the lid to translate into an engaged structure with the lid beingpivotable while in the engaged structure.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects and advantages of the presentinvention will be described with reference to the following drawings.

FIG. 1 is a rear perspective view of a breathing assistance apparatusthat is arranged and configured in accordance with certain features,aspects and advantages of the present invention.

FIG. 2 is an enlarged rear top perspective view of a hinge of thebreathing assistance apparatus of FIG. 1 with a lid in a closedposition.

FIG. 3 is an enlarged front perspective view of the hinge of FIG. 2showing the lid in an opened position.

FIG. 4 is a sectioned perspective view of the hinge of FIG. 2 showingthe lid in a partially closed position.

FIG. 5 is a front perspective view of the lid of the breathingassistance apparatus of FIG. 1, which lid is arranged and configured inaccordance with certain features, aspects and advantages of the presentinvention.

FIG. 6 is a rear bottom perspective view of a latch member of the lid ofFIG. 5.

FIG. 7 is a rear bottom perspective view of the latch member of FIG. 6shown assembled to the lid.

FIGS. 8A-8D are side views of a guide structure of the hinge of FIG. 2in several positions from opened to closed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates a breathing assistance apparatus 100 that is arrangedand configured in accordance with certain features, aspects andadvantages of the present invention. The apparatus 100 comprises a mainbody 102 and a lid 104. Together, the main body 102 and the lid 104define a housing 106 that encloses, or generally encases, a reservoir,tub, tank or other body of liquid (not shown) within a cavity.

The illustrated body 102 comprises at least one outer surface 110. Inthe illustrated configuration, the body 102 comprises four generallyplanar outer surfaces 110 that are connected by rounded corners 112.Other configurations are possible.

The lid 104 is connected to the body 102 with hinge assemblies 114. Inthe illustrated configuration, the lid 104 is connected to a rear of themain body 102 using two hinge assemblies. The lid 104 can be connectedto other surfaces. In addition, the lid 104 can be connected to the mainbody 102 using as few as one hinge assembly 114 or more than two hingeassemblies 114. Preferably, the hinge assemblies 114 are constructedsuch that, with the lid 104 in the closed position (e.g., as shown inFIG. 1), the hinge assemblies 114 are generally flush with or recessedinto the rear outer surface 110. In some configurations, the hingeassemblies 114 are constructed such that the hinge assemblies do notprotrude rearward of the rear outer surface 110. In some configurations,some of the hinge features may protrude very slightly from one or moresurrounding surface of the rear outer surface or other surroundingportion of the apparatus. In some configurations, the lid 104 comprisesan outer perimeter 116 and the hinge assemblies 114 do not protrudesignificantly outward of the outer perimeter 116 of the lid 104.

With reference to FIG. 2, the hinge assemblies 114 comprise at least onepost 120 and at least one support 122. Preferably, the at least one post120 is mounted such that the post is recessed and located inside of theouter perimeter 116 of the lid. The illustrated configuration comprisesa single post 120 that is connected to two supports 122. In someconfigurations, the at least one post 120 is mounted to the lid 104while the at least one support 122 is mounted to the main body 102. Insome configurations, the at least one post 120 can be mounted to themain body 102 while the at least one support 122 can be mounted to thelid 104.

The at least one post 120 can be secured to the lid 104 using one ormore standoffs 124. In the illustrated construction, the standoffs 124are positioned between the two supports 122. The standoffs reduce thedeflection of the post 120 in the region of the supports 122. In someconfigurations, the portion 126 of the post 120 extending between thestandoffs 124 can be omitted. In the illustrated configuration, however,the portion 126 of the post 120 can be secured by a clip 130. The clip130 can have a recess that accommodates the post 120 or any othersuitable configuration.

A force generated by the clip 130 on the post 120 in the illustratedconfiguration is opposed by forces generated by the supports 122, forexample. The clip 130 can contact an opposite side of the post 120relative a contact region between the supports 122 and the post 120. Insome configurations, the clip 130 can be configured to deflect away fromthe post 120 during assembly of the post 120 and the clip 130. Forexample, the clip 130 can be a deflectable finger that extends rearwardfrom the main body 102. The supports 122 can have a recess that definesa rearwardly-opening mouth that receives at least a portion of acircumference of the post 120. Accordingly, movement of the post 120 inthe directions shown by the arrow can result in attachment anddetachment of the post 120 relative to the supports 122 and the clip130. The rearwardly-opening mouth of the supports 122 also results in astructure that overlies the post 120 such that vertical movement of thepost 120 relative to the supports 122 is not possible with the post 120fully received within the mouths of the supports 122. As such, the lid104 is unlikely to separate from the main body 102 during therapy.

With reference to FIG. 3, the lid 104 and the main body 102 can includestructures that guide the post 120 and the clip 130 and supports 122into connection. In some configurations, the structures facilitatemovement of the at least one post 120 into the mouth of the supports 122and into engagement with the clip 130 when the lid 104 is brought towardthe closed position on the main body 102. In the illustratedconfiguration, two guide structures 140 are positioned outboard of thetwo supports 122. Other configurations also are possible.

With reference to FIG. 4, the guide structure 140 comprises a recess 142that receives a cam structure 144. The cam structure 144 is receivedwithin the recess 142 such that, with the lid 104 moved to the fullyclosed position on the main body 102, the cam structure 144 does notprevent the lid 104 from fully closing. The cam structure 144 taperstoward a point with a sloping surface 146 such that the thickness of thecam structure 144 increases from back to front while the guide structurehas an opposing surface 150. The sloping surface 146 and the opposingsurface 150 engage each other such that the sloping surface 146 and theopposing surface 150 resists movement of the lid 104 relative to themain body 102 in the detachment direction (see FIG. 2) when the lid 104is in an at least partially closed position.

Moreover, as the lid 104 is rotated toward a closed position (e.g., FIG.1), the sloping surface 146 and the opposing surface 150 act to draw thelid 104 forward into the attachment position (e.g., the at least onepost 120 connected to the supports 122 and the clip 130). Thus, rotationof the lid 104 can result in the hinge assemblies 114 being operativelyconnected from a detached state. In some configurations, the differencein thicknesses of the sloping surface 146 and the opposing surface 150from initial contact to fully closed is substantially the same as adistance from the outer surface of the post 120 and the first contactwith the supports 122 such that as the sloping and opposing surfaces146, 150 are moved into full engagement along their lengths, the post120 is pulled into position within the supports 122 and the clip 130.

Notably, with the lid 104 in the open position (e.g., FIG. 3) relativeto the main body 102, sufficient space exists between the slopingsurface 146 and the opposing surface 150 such that the lid 104 can beseparated from the main body 102 with the application of force.Advantageously, such a construction allows separation between the lid104 and the main body 102 by disconnection of the posts 120 from thesupports 122 and the clips 130. Such a separation can protect theapparatus 100 from damage resulting from forces that result fromover-opening of the lid or from possible misuse of the apparatus 100.Accordingly, the ability to separate the lid 104 from the main body 102can protect the apparatus 100 from permanent damage. As discussed above,the lid 104 can be easily reconnected by placing the posts 120 alongsidethe supports 122 and rotating the lid 104 toward a closed position,which results in the sloping surface 146 of the cam structure 144 andthe opposing surface 150 of the guide structure drawing the componentsback together.

With reference now to FIG. 5, a release and handle assembly 160 of thelid 104 will be described. As illustrated, the release and handleassembly 160 comprises at least one button member 162 that is mounted onthe lid 104. In some configurations, the button member 162 is mountedfor movement toward and away from the hinge assemblies 162. In someconfigurations, the button member 162 can be mounted along a side of thelid 104 that is adjacent to the side of the lid 104 having the hingeassemblies 162. In the illustrated configuration, the button member 162is mounted on an opposing side of the lid 104 relative to the hingeassemblies 114 and capable of movement toward and away from the hingeassemblies 114.

The button member 162 is illustrated in FIG. 6. The button membercomprises an exterior surface 164, which is best shown in FIG. 5. Theexterior surface 164 is sufficiently large for contact with a finger orthumb. As also illustrated in FIG. 5, the lid 104 can comprise acomponent 166 that is used to raise the lid 104. In the illustratedconfiguration, the component 166 is a recessed region that has a wall170 extending generally parallel with the exterior surface 164.Preferably, the recessed region 166 is sufficiently large as toaccommodate at least tips of fingers. In some configurations, thecomponent 166 is one or more lip, ridge, protrusion, recess or the like.Accordingly, the component 166 (e.g., having the wall 170) and theexterior surface 164 can allow a simple squeezing action to accomplishboth an unlatching of the button member 162 as well as providing agrasping action to allow movement of the lid 104 away from the main body102.

With reference again to FIG. 6, the illustrated button member 162comprises two outer posts 172. The posts 172 are sized and configured toengage with biasing members, such as compression springs or the like,for example but without limitation. The posts 172 are received withincorresponding housings 174 that are formed in the lid 104. The housings174 can contain the biasing members and the posts 172 can slide into andout of the housings 174 against the biasing force of the biasingmembers.

The illustrated button member 162 also comprises at least one tab 176.In the illustrated configuration, the button member 162 comprises twotabs 176. The tabs 176 are bayonet shaped with a barb 180 at the end. Asshown in FIG. 7, the tabs 176 can engage a structure 182 formed in thelid 104. Thus, the tabs 176 in cooperation with the structure reduce thelikelihood of the button member 162 coming out of a recess of the lid104 while allowing inward depression of the button member 162 relativeto the lid 104.

The structure 182 also comprises a passage 184 that receives a finger186 mounted to, or formed on, the button member 162. The passage 184facilitates generally only linear translation of the button member 162relative to the lid 104. In other words, the passage 184 receives thefinger 186 and the finger 186 is generally limited by the passage 184 tosubstantially linear movement.

The finger 186 supports a locking post 190. The locking post 190 canengage with a structure formed on the main body 102. In someconfigurations, the locking post 190 engages with a structure formed onan inner surface of the main body 102 such that the depression of thebutton member 162 results in separation between the locking post 190 andthe structure with which it normally engages. Releasing of the buttonmember 162 results in the biasing members moving the locking post 190into position for reengagement with the structure with which it normallyengages.

FIGS. 8A-8D illustrate the lid 104 in several positions relative to themain body 102. FIG. 8A illustrates the lid 104 in a first openedposition. FIGS. 8B and 8C illustrate the lid 104 in progressivelyfurther closed positions relative to the first opened position of FIG.8A. FIG. 8D illustrates the lid 104 in a closed position. In particular,FIGS. 8A-8D further illustrate the interaction between the slopingsurface, or cam surface, 146 of the cam structure 144 and the opposingsurface (also referred to as a guide surface or cam follower surface)150 of the lid recess 142 as the lid 104 moves from an opened positionto a closed position. As described herein, the cam structure 144 and therecess 142 can interact to move the lid 104 from a detached positionrelative to the main body 102 to an attached position relative to themain body 102 when the lid 104 is moved from an opened position to aclosed position.

As described herein, the support 122 includes the recess 200 comprisingthe mouth 202, which opens in a rearward direction in the illustratedarrangement. Preferably, the recess 200 is elongate in shape and extendsin a generally fore-aft direction. In the illustrated arrangement, therecess 200 is generally or substantially horizontal or aligned with abottom support surface of the main body 102 such that the recess 200 isgenerally or substantially horizontal when the apparatus 100 is restedon a flat surface. The recess 200 includes upper and lower guidesurfaces 204 that extend forwardly from the mouth 202 to an end surface206. As described herein, the support 122 also assists in retaining thelid 104 on the main body 102 in response to forces within the housing106 (e.g., forces resulting from internal pressure) tending to separatethe lid 104 from the main body 102. Thus, the upper portion of the endsurface 206 and/or the upper guide surface 204 can form a retentionsurface that contacts the post 120 to retain the lid 104, or at least aportion of the lid 104 near the support 122 and/or hinge 114 (e.g., arearward portion), on the main body 102 in response to forces tending toseparate the lid 104 from the main body 102.

In the illustrated arrangement, the end surface 206 is curved (e.g.,semi-circular) in shape from a side view and connects the upper guidesurface 204 and the lower guide surface 204. The illustrated support 122is elongate in a lateral or side-to-side direction and, thus, defines asubstantially semi-cylindrical shape in three dimensions. However, forconvenience, the hinge 114, guide structure 140 and cam structure 144may be described herein in the context of the side views of FIGS. 8A-8Din two-dimensional terms. It will be appreciated that the describedstructures also have a width dimension relative to the apparatus 100 ora depth dimension relative to the side view of FIGS. 8A-8D.

The illustrated end surface 206 is defined by a curve having a radius208 from a center point 210 (or an axis in three dimensions). The recess200 can have a longitudinal axis 212 that extends along a length of therecess 200 generally from the mouth 202 to the end surface 206 and, inthe illustrated configuration, passes through the center point 210. Theaxis 212 can be aligned with or parallel to one or both of the upper andlower guide surfaces 204 or can be centrally-located between the guidesurfaces 204 (such as in the event of a tapered recess, for example andwithout limitation). In the illustrated configuration, the axis 212 isgenerally or substantially horizontal (or parallel to a bottom surfaceof the main body 102). However, in other configurations, the axis 212could be non-horizontal or angled relative to the bottom surface of themain body 102).

As described herein, the post 120 preferably is cylindrical in shape orcircular in shape from a side view, as illustrated in FIGS. 8A-8D. Thepost 120 defines a center point 214 (or an axis in three dimensions) anda radius 216. Preferably, the radius 216 of the post 120 issubstantially equal to the radius 208 of the end surface 206 such thatthe post 120 can be snugly positioned against the end surface 206 andrestrained in a vertical direction within recess 200 with the centerpoints 210, 214 substantially aligned or coaxial with one another.

Preferably, the cam surface or sloping surface 146 of the cam structure144 is positioned or oriented relative to the end surface 206 and/orcenter point 210 such that the post 120 is moved along the axis 212 ofthe recess 200 toward the end surface 206 as the lid 104 is moved fromthe opened toward the closed position. In the illustrated arrangement, afirst distance 220 is defined between a first point or location 222 onthe sloping surface 146 and the center point 210 and a second distance224 is defined between a second point or location 226 on the slopingsurface 146 and the center point 210. Preferably, the first point 222 islocated on an initial portion of the sloping surface 146 and the secondpoint 226 is located on a subsequent portion of the sloping surface 146such that the opposing surface 150 will contact the first point 222before the second point 226 as the lid 104 is moved from an openedposition to a closed position. The first point 222 can be at or near thelocation that is first contacted by the opposing surface 150 duringclosing of the lid 104 and the second point 226 can be at or near thefurthest location along the sloping surface 146 contacted by theopposing surface 150 when the lid 104 is in the closed position. Thefirst distance 220 preferably is smaller than the second distance 224,which causes the movement of the post 120 along the axis 212 of therecess 200 as the lid 104 is moved from an opened position to a closedposition and the opposing surface 150 moves along the sloping surface146 in a direction from the first point 222 towards the second point226.

A distance 228 traveled by the center point 214 of the post 120 withinthe recess 200 when the lid 104 is closed preferably is substantiallyequal to a difference 230 between the second distance 224 and the firstdistance 220. The distance 228 can be less than an overall length of therecess 200 because the post 120 can be at least partially located withinthe recess 200 prior to being drawn to the end surface 206 by the guidestructure 140. In other arrangements, the distance 228 could besubstantially equal to a length of the recess 200. Although thedistances described immediately above are in relation to the centerpoints 210 and 214, the distances similarly could be measured relativeto other points on locations on the recess 200 (e.g., end surface 206)and post 120, respectively, if desired, such as in the context ofnon-circular (or non-cylindrical) recess or post shapes.

FIG. 8A illustrates the lid 104 in a first open position relative to themain body 102, which may be a fully opened position, such as wheninitiating a process of reattachment of the lid 104. As illustrated, theopposing surface 150 is clear of the sloping surface 146 such thatrearward movement (e.g., detachment) of the lid 104 is permitted.Advantageously, such an arrangement reduces the likelihood of permanentdamage resulting from excessive opening forces applied to the lid 104.FIG. 8B illustrates the lid 104 in a second open position that isfurther towards a closed position relative to the first open position ofFIG. 8A. In FIG. 8B, the opposing surface 150 remains clear of thesloping surface 146. That is, a vertical gap exists between a bottom ofthe opposing surface 150 and a top of the sloping surface 146.

FIG. 8C illustrates the lid 104 in a third open position that is furthertowards a closed position relative to the positions of FIGS. 8A and 8B.In the position of FIG. 8C, a leading portion or engagement portion 232of the opposing surface 150 is engaged with or contacts an initialportion of the sloping surface 146, which may be at or near the firstpoint or location 222. In the illustrated arrangement, the post 120 isspaced away from the end surface 206 of the recess 200. FIG. 8Dillustrates the lid 104 in a position that is further towards a closedposition than the positions of FIGS. 8A-8C. The position of FIG. 8D canbe a fully closed position of the lid 104. In the illustratedarrangement, at least the leading portion or engagement portion 232 ofthe opposing surface 150 is engaged with or contacts a subsequentportion of the sloping surface 146 spaced from the initial portion. Thesubsequent portion may be at or near the second point or location 226.Preferably, the post 120 is snugly positioned against the end surface206 in the position of FIG. 8D. Thus, preferably, a distance between theengagement surface 232 and the center point 214 is preferablysubstantially equal to the second distance 224.

As described herein, the interaction of the guide structure 140 and thecam structure 144 as illustrated in FIGS. 8A-8D may occur only during areattachment or engagement procedure for the lid 104. In normal openingand closing movement, sliding of the post 120 (or significant sliding ofthe post 120) within the recess 200 may not occur. Advantageously, suchan arrangement reduces wear by reducing the amount of sliding movementbetween components during normal use. However, other arrangements arepossible in which the sliding movement of the post 120 occurs more oftenthan only during engagement of the lid 104, such as during normalopening and closing of the lid 104.

Although the illustrated opposing surface 150 has a similar size andshape as the sloping surface 146 and extends along a substantial portionof the sloping surface 146 when the lid 104 is in the closed position,other arrangements are also possible. For example, the opposing surface150 could be a smaller surface, such as a cam follower surface, definingan engagement portion 232 that contacts only a point or small length ofthe sloping surface 146 in any one position. The engagement portion 232could be rotatable such that it rolls along the sloping surface 146, ifdesired. Moreover, as disclosed herein, the illustrated arrangementscould be reversed such that the cam surface or sloping surface 146 iscarried by the lid 104 and the opposing surface 150 (or cam followerwith engagement portion 232) is carried by the main body 102.

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise”, “comprising”, and thelike, are to be construed in an inclusive sense as opposed to anexclusive or exhaustive sense, that is to say, in the sense of“including, but not limited to”.

Reference to any prior art in this specification is not, and should notbe taken as, an acknowledgement or any form of suggestion that prior artforms part of the common general knowledge in the field of endeavour inany country in the world.

The invention may also be said broadly to consist in the parts, elementsand features referred to or indicated in the specification of theapplication, individually or collectively, in any or all combinations oftwo or more of said parts, elements or features.

Where, in the foregoing description reference has been made to integersor components having known equivalents thereof, those integers areherein incorporated as if individually set forth.

It should be noted that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modifications may be madewithout departing from the spirit and scope of the invention and withoutdiminishing its attendant advantages. It is therefore intended that suchchanges and modifications be included within the scope of the invention.

What is claimed is:
 1. A breathing assistance apparatus comprising: amain body comprising a cavity, the main body comprising a front portionpositioned forward of a rear portion; a lid configured to rotate betweenan opened position and a closed position closing the cavity, the lidbeing separable from the main body from an attached state to a detachedstate in a detachment direction; a hinge assembly connecting the lid tothe rear portion of the main body, the hinge assembly comprising: a postmounted to one of the lid or the main body; a support mounted to theother of the lid or the main body, wherein the support is configured toreceive at least a portion of the post; a cam structure; and a guidestructure configured to interface with the cam structure to draw the lidforward into the attached state; the guide structure and the camstructure located forward of the post when the lid is in the closedposition, wherein when the lid is moved from the detached state to theattached state, the lid slides toward the front portion of the main bodysuch that the support receives the at least the portion of the post. 2.The breathing apparatus of claim 1, wherein the post is mounted to thelid and the support is mounted to the main body.
 3. The breathingapparatus of claim 1, wherein the post is mounted to the main body andthe support is mounted to the post.
 4. The breathing apparatus of claim1, wherein the support comprises a recess configured to receive the atleast the portion of the post.
 5. The breathing apparatus of claim 1,wherein the hinge comprises a clip extending along at least an axiallength of the post.
 6. The breathing apparatus of claim 5, wherein thepost is captured between the clip and the support.
 7. The breathingapparatus of claim 1, wherein when the lid is in the opened position,the lid is separable from the main body with application of a sufficientforce without breakage of either the support or the post.
 8. Thebreathing apparatus of claim 1, wherein when the lid is in the openedposition, the guide structure is sufficiently spaced from the camstructure such that movement of the lid in the detachment direction ispermitted.
 9. The breathing apparatus of claim 1, wherein the camstructure comprises a sloping surface such that the cam structure taperstoward a tip.
 10. The breathing apparatus of claim 9, wherein the guidestructure comprises an opposing surface configured to interface with thesloping surface of the cam structure.
 11. The breathing apparatus ofclaim 1, wherein the cam structure and the guide structure areconfigured to resist movement of the lid relative to the main body inthe detachment direction when the lid is in an at least partially closedposition.
 12. The breathing apparatus of claim 1, wherein the detachmentdirection is a rearward direction.
 13. The breathing apparatus of claim1, wherein the lid is configured to move from the detached state to theattached state as the lid is rotated from the opened position to theclosed position.
 14. A breathing assistance apparatus comprising: a mainbody comprising a cavity, the main body comprising a front portionpositioned forward of a rear portion; a lid configured to rotate betweenan opened position and a closed position closing the cavity, the lidbeing separable from the main body from an attached state to a detachedstate in a detachment direction; a hinge assembly connecting the lid tothe rear portion of the main body, the hinge assembly comprising: a postmounted to one of the lid or the main body; a support mounted to theother of the lid or the main body, wherein the support is configured toreceive at least a portion of the post; a cam structure; and a guidestructure configured to interface with the cam structure, the guidestructure and the cam structure located forward of the post when the lidis in the closed position, wherein the guide structure only interfaceswith the cam structure during movement between the attached state andthe detached state; wherein when the lid is moved from the detachedstate to the attached state, the lid slides toward the front portion ofthe main body such that the support receives the at least the portion ofthe post.